This project was designed to facilitate structure determination from electron microscopy by providing suitable software, hardware, and scientific expertise to allow other scientists, primarily at NIH, to use image processing and computer reconstruction to determine or understand a specimen's structure. Two new applications that began this year are analysis and identification of small particles by electron beam excited x-ray microanalysis as applied to aqueous suspensions of vertebrate retinal rod cells and the analysis of the microtrabecular lattice and the cytoskeleton to determine their volume, surface area, and the diffusion of molecules through it. Studies continued from FY82 include analysis of keratin, membrane structure, and muscle structure.